Rotational and vibrational process for molding cellulosic fibers

Abstract

A molding process and apparatus produces molded parts from cellulosic fibers. A dry process molds cellulosic fibers including the steps of mixing the cellulosic fibers and a binder to form a substantially homogeneous mixture; distributing the mixture to a desired pre-form, preferably having a non-uniform cross-section; and molding the pre-form, under a predetermined pressure and heat, to form a molded part having a substantially uniform density. A distribution assembly distributes the mixture to a desired pre-form by rotational and/or vibrational motion. The rotor on the upper surface of the telescoping portion of the distribution assembly cylindrically rotates to mechanically move the mixture in a desired pre-form shape. The rotor may be unevenly weighted such that as it rotates, the distribution assembly vibrates thereby mechanically distributing the mixture by causing it to settle in the cartridge in the desired pre-form shape.

What is claimed is: 
     
       1. A process for molding cellulosic fibers comprising the sequential steps of: mixing cellulosic fibers and a binder to form a substantially homogeneous mixture;   receiving the mixture in a pre-form cartridge and distributing the mixture therein;   redistributing the mixture within the pre-form cartridge prior to molding a pre-form having a cross-section of varied thickness by imparting rotational motion to the mixture in such a manner that some of the mixture is moved toward outer peripheral edges of the pre-form cartridge; and   molding the pre-form from the redistributed mixture within the pre-form cartridge, under a predetermined pressure and heat, forming a molded part having said cross-section of varied thickness and a substantially uniform density throughout.   
     
     
       2. The process according to claim 1 wherein the binder is selected from the group consisting of lignin based adhesives, agricultural by-products, synthetic polymers including thermoplastics and thermoset resins. 
     
     
       3. The process according to claim 1 wherein the binder is high density polyethylene. 
     
     
       4. The process according to claim 1, wherein the binder is high density polyethylene fibers. 
     
     
       5. The process according to claim 1, wherein the binder is high density polyethylene granules. 
     
     
       6. The process according to claim 1 wherein the binder is polypropylene fiber. 
     
     
       7. The process according to claim 1 wherein the binder is polypropylene. 
     
     
       8. The process according to claim 1 wherein the binder is polypropylene granules. 
     
     
       9. The process according to claim 1 wherein the binder is low density polyethylene. 
     
     
       10. The process according to claim 1 wherein the binder is low density polyethylene fiber. 
     
     
       11. The process according to claim 1 wherein the binder is low density polyethylene granules. 
     
     
       12. The process according to claim 1 wherein the binder is polyethylene granules. 
     
     
       13. The process according to claim 1 wherein the cellulosic fiber is recycled paper. 
     
     
       14. The process according to claim 1 wherein the cellulosic fiber is derived from disposable diaper scraps. 
     
     
       15. The process according to claim 1 further comprising the step of applying one of a laminate and coating to the pre-form prior to the molding step. 
     
     
       16. The process according to claim 1 wherein the molding step comprises the steps of applying steam to the pre-form and vacuuming moisture from the pre-form. 
     
     
       17. The process according to claim 1 wherein the molding step comprises the steps of applying steam to the pre-form while the preform is being pressed and heated and using a vacuum to remove moisture from the pre-form. 
     
     
       18. The process according to claim 1 wherein pressure during the molding step is 4000-5000 psi. 
     
     
       19. The process according to claim 1, wherein the mixture is distributed by rotating a piston assembly disposed within the pre-form cartridge such that some of the mixture is moved toward outer peripheral edges of the pre-form and toward vertical sidewalls of the piston assembly. 
     
     
       20. The process according to claim 1, further comprising settling the mixture, after redistributing the mixture, by imparting vibrating motion to the mixture. 
     
     
       21. The process according to claim 1, further comprising settling the mixture, after redistributing the mixture, by imparting rotating motion to the mixture. 
     
     
       22. A dry process for molding paper comprising the sequential steps of: processing the paper into fibers;   mixing the paper fibers and a thermosetting binder to form a substantially homogeneous mixture;   distributing the mixture in a cartridge and forming therein a desired pre-form having a non-uniform cross-section;   transferring the pre-form to a mold;   molding the pre-form to form a molded part having a substantially uniform density by heat and pressures of 4000-5000 psi; and   ejecting the molded part from the mold.